The present invention relates to a particle beam irradiation system suitable for a particle beam treatment making use of a charged particle beam (ion beam) of protons or heavy ions. More particularly, the invention relates to a particle beam irradiation system capable of controlling changes in beam energy and providing operation cycle updates in a short time, and to an operating method for the system.
The particle beam treatment is known as cancer radiotherapy whereby the affected part of a cancer patient is irradiated with an ion beam of protons or heavy ions for treatment. One method of ion beam irradiation is a scanning irradiation method such as one disclosed in “Review of Scientific Instruments,” Vol. 64, No. 8 (August 1993), pp. 2074-2093 (hereinafter, referred to as Non-patent Document 1).
Where a synchrotron is adopted as an ion beam generator for controlling changes in beam energy as required of the scanning irradiation method as a method for providing the control in a short time, there is available a multistage extraction control operation for bringing about irradiation with an ion beam at a plural energy stages within one operation cycle of the ion synchrotron, as disclosed in Japanese Patent No. 4873563 (hereinafter, referred to as Patent Document 1), JP-2011-124149-A (hereinafter, referred to as Patent Document 2), and “Nuclear Instruments and Methods in Physics Research,” No. A624 (September 2010), pp. 33-38 (hereinafter, referred to as Non-patent Document 2).